Tubing hanger assembly and method of using same for hanging tubing in a well under pressure

ABSTRACT

A tubing hanger assembly and method of using same for hanging tubing in a well under pressure, wherein tubing having a smooth external surface and a check valve at its lower end, is gripped and sealed off in the hanger and then the wellhead equipment above the tubing hanger is removed so that the tubing is thereafter available for injecting chemicals into the well and for performing similar well operations.

United States Patent Slator et al.

[ 51 Sept. 12, 1972 TUBING HANGER ASSEMBLY AND METHOD OF USING SAME FOR HANGING TUBING IN A WELL UNDER PRESSURE Inventors: Damon T. Slator; Archie W. Peil,

both of Houston, Tex.

Assignee: Bowen Tools, Inc. Filed: Oct. 16, 1970 Appl. No.: 81,313

US. Cl ..166/3l5, 166/86 Int. Cl ..E2lb 33/03, E2lb 43/00 Field of Search ....l66/75, 86, 88, 315; 285/141,

References Cited UNITED STATES PATENTS 2/1931 Barker ..285/145 2,243,598 5/1941 Flemming et al. ..27-7/1l0 1,838,503 12/1931 Shaffer ..l66/86 1,908,221 5/1933 Church 251/1 2,150,887 3/1939 Mueller et a1. ..277/1 10 2,300,854 11/1942 Allen et al. ..l66/224 2,902,302 9/ 1 959 Ackermann ..277/1 10 Primary Examiner.lames A. Leppink Attorney-Pravel, Wilson & Matthews [5 7 ABSTRACT A tubing hanger assembly and method of using same for hanging tubing in a well under pressure, wherein tubing having a smooth external surface and a check valve at its lower end, is gripped and sealed off in the hanger and then the wellhead equipment above the tubing hanger is removed so that the tubing is thereafter available for injecting chemicals into the well and for performing similar well operations.

2 Claims, 4 Drawing Figures PATENTEDSEP 12 I912 3.690.381

SHEET 1 BF 2 o .50/770/7 7. J/afa/ Arcfi/e 14 e// J E C INVENTORJ' ATTORNEYS PATENTED 12 3.690.381

sum 2 or 2 l@ phone! when &MaHLewA HTTORNE YS TUBING HANGER ASSEMBLY AND METHOD OF USING SAME FOR HANGING TUBING IN A WELL UNDER PRESSURE BACKGROUND OF THE INVENTION The field of this invention is tubing hanger assemblies and methods of using same.

Inrecent years, tubing in continuous lengths without joints or collars has been introduced into wells through the usual wellhead equipment, an example of which is illustrated in U.S. Pat. No. 3,313,346. So long as the wellhead equipment is in place, the tubing may be used for performing various operations such as the injection of gas to stimulate the flow of oil from a well and the injection of paraffm solvents and other chemicals. If only one or more of such operations is to be performed, the tubing and the wellhead equipment can simply be removed after the operation, but in some instances, periodic operations on a weekly or monthly basis are required, and it is therefore desirable to have the tubing in the well, but the wellhead equipment and injection apparatus are too expensive to leave in an idle condition for such extended periods between the operations.

SUMMARY OF THE INVENTION The present invention relates to a new and improved tubing hanger and method of using same in a well under pressure. In carrying out the method, when the well is under pressure, the tubing has a check valve at its lower end to prevent the well pressure from flowing fluids upwardly, and the tubing hanger is in position below the usual wellhead equipment above the well casing. After the tubing is gripped and externally sealed off by the tubing hanger, the tubing is supported in the hanger so that the wellhead equipment thereabove can be removed, and the tubing above the hanger can be cut off without danger of losing the well pressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of the apparatus of this invention in position during the injecting of tubing into a well casing;

FIG. 2 is a vertical sectional view, partly in elevation, of the tubing hanger of this invention prior to the disconnection of the wellhead equipment therefrom;

FIG. 3 is a cross-sectional view taken on line 3-3 of FIG. 2; and

FIG. 4 is a view similar to FIG. 2, but showing the tubing hanger of this invention in position for supporting the tubing and packing off around the external surface of the tubing, and with the tubing cutnear the upper end of the tubing hanger for a permanent mounting after the wellhead equipment thereabove has been removed.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, the letter T designates generally the tubing hanger assembly of this invention which is adapted to be positioned above a well casing C (FIG. 1) and below the conventional wellhead equipment W. The typical wellhead equipment W illustrated in FIG. 1 includes blowout preventers and other controls which form no part of the present invention. Continuous tubing or pipe P which is normally formed without any tubing P in the casing C, such tubing P may be supported by the tubing hanger assembly T, so that the wellhead equipment W as well as the injector apparatus A may be removed.

Considering the invention more in detail, the tubing hanger assembly T includes an upper body section 10, and a lower body section 1 l which form the body of the hanger assembly T and which are joined by a cylindrical expander actuator 12, the purpose of which will be explained hereinafter. The expander actuator 12 has upper threads 12a which are in threaded engagement with threads 10a of the upper body section 10 so that upon rotation of the actuator 12, it moves downwardly relative to the upper body section 10. The actuator 12 has lower internal threads 12b which are in threaded engagement with external threads 11a on the lower body section 11 so that as the threads 10a and 12a are unthreaded from each other, the threads 12b make up on the threads 11a, thereby keeping the body sections 10 and 11 connected with each other through the actuator 12 as the actuator 12 is rotated, as will be more evident hereinafter.

The upper body section 10 has a longitudinal bore 10b therethrough, which, at its smallest diameter is still larger than the external diameter of the pipe P so that the pipe P may pass freely through the tubing hanger T. The body section 11 likewise has a longitudinal bore 1 1b which is at least as large as the diameter of the bore 10b, and preferably is larger throughout most of its length.

The upper end of the body section 10 has external threads 10c (FIG. 2) which may be utilized for connecting to a union 15 (FIG. 1) of any conventional construction, or to any other suitable means for attaching to the wellhead equipment W thereabove. Such threads 10c also serve for the attachment of a closure means K (FIG. 4), the details of which will be explained hereinafter. Such closure means K is mounted on the body section 10 after the wellhead equipment W has been removed from the body section 10.

The body section 10 preferably has an annular shoulder 10d which serves as a support for a pair of gripping and support members 20 (FIGS. 2 and 3). Each of the members 20 is preferably semi-cylindrical and is formed with gripping teeth 20a on a curved surface which has a radius conforming with the radius of the tubing T so that when the members 20 are moved inwardly into gripping engagement with the external surface of the tubing P, the teeth 20a engage and bite into the surface of the tubing P to facilitate the gripping action. The external surface 20b of each of the members 20 is preferably in engagement with the body 10 in the recess 10e when the members 20 are in the retracted position (FIGS. 2 and 3) out of contact with the pipe P. The inner surfaces 200 of each of the members 20 are formed on a radius or diameter and are preferably flat so that they limit the extent of inward movement of the members 20 towards each other, thereby preventing a crushing force from being applied to the tubing P by the members 20 as they are moved inwardly into the gripping position.

Each of the members 20 is preferably formed with a dovetail slot 20d which receives a correspondingly tapered end 21a on an operating rod or screw 21. Such construction facilitates the assembly of the gripping members 20 on the operating rods 21 since the operating rods 21 may be positioned through the wall of the body section (FIG. 2) and then the members may be moved or dropped downwardly longitudinally with the flared or tapered ends 21a in the slots 20d. After the rods 21 are thus assembled on the gripping members 20, radial or lateral movements of the rods 21 are then transmitted to the members 20 for lateral movements of such members 20 inwardly to grip the tubing P, or outwardly to release such gripping action.

Although the operating rods 20 may be mounted directly through the wall of the body section 10, they are preferably threaded into a fixed insert 23 which is threaded or is otherwise secured through the wall of the body section 10. The insert 23 has internal threads 23a which coact with external threads 21b on each operating rod 21, so that upon rotation of the rod 21, it moves its respective gripping member 20 inwardly and outwardly, depending upon the direction of movement of the rods 21. A stop nut 24 is secured to each operating rod 21 inwardly of wrench flats 210 (FIG. 2), which stop 24 serves to limit the inward travel of the rod 21. Suitable O-rings 25 and 26 are provided to prevent the escape of fluid around the operating rod 21 and the insert 23.

The gripping members 20 are retained in the body section 10, in a seated position on the annular shoulder 10d by an annular retaining ring 27 (FIG. 2) which is held in place by a snap-ring 28 fitting into a groove 10f in the body section 10. Since the snap-ring 28 is removable, the ring 27 is therefore removable, thereby permitting the removal of the gripping members 20 if desired. Also, it will be appreciated that such construction facilitates the assembly of the tubing gripping and supporting means heretofore described.

The lower body section 11 has a counterbore or recess 11c, forming an annular lateral shoulder 11d for receiving a resilient packing element 30 formed of rubber or other suitable resilient material. The external circumferential surface 30a of the packing element 30 is in engagement with the bore 110, while the inner surface 30b of the packing element 30 is of a diameter which is approximately the same as that of the longitudinal bore 10b and 11b so as to normally be out of contact with the external surface of the tubing or pipe P (FIG. 2).

A packing expander sleeve 32 is formed of steel or other similar relatively hard material and it is disposed above the packing member 30 for longitudinal movement within the bore 11c of the lower body section 11 for laterally distorting the packing member 30 by compressing same to form a seal between the inner surface 30b and the external surface of the tubing P. To facilitate such lateral distortion of the packing member 30 by the longitudinal downward movement of the expander sleeve 32, the sleeve 32 preferably has a downwardly and outwardly tapered lower surface 32a which engages a correspondingly inclined or tapered upper surface 300 on the packing member 30. The inside diameter 32b of the sleeve 32 is preferably of the same diameter as the inside bore or surface 30b of the packing element 30 when it is in the normal undistorted condition (FIG. 2).

An external shoulder 320 is formed in the expander sleeve 32 for receiving an inwardly extending shoulder on the expander actuator 12 so that downward movements of the actuator 12 are transmitted to the expander sleeve 32. Suitable O-rings 33 and 34, formed of rubber or other suitable material are preferably provided to seal off the threads above and below such seals from the fluid which may be inside of the tubing hanger. The actuator 12 maybe rotated in any suitable manner, but as illustrated in the drawings, spanner wrench holes 12d are provided in the external surface thereof for engagement by a conventional spanner wrench in the known manner for imparting rotation to the actuator 12 relative to the body formed by the sections 10 and 11.

The closure or control assembly K illustrated in particular in FIG. 4 is added after the wellhead assembly W has been removed, as will be more fully explained. Such control assembly K is constructed so that it fits over the upper end of the pipe or tubing P after it has been cut off at a point just above the tubing hanger T. Thus, the closure or control assembly K, as illustrated in FIG. 4, includes an adapter 40 which has internal threads 40a in threaded engagement with the external threads 10c on the upper end of the upper body section 10. Upper external threads 40b are also formed on the adapter 40 for engagement by a retaining ring 41 having a flange 41a therewith for engagement with an annular projection or lug 42a on a closure cap 42. The closure cap 42 preferably has an O-ring 43 formed of rubber or similar material therewith which forms a seal between the cap 42 and the adapter 40. Also, a pipe or tube 44 extends from the cap 42 and establishes communication between the interior and the exterior thereof so that suitable valves and other control equipment may be provided for introducing or releasing fluid from the tubing P as desired. Since the tubing P has a check valve 50 (FIG. 2) at or near its lower end prior to the lowering of the tubing P into the well, fluid flow is permitted in only a downward direction through the tubing P. This permits the injection of chemicals, paraffin solvents, gas to stimulate the flow of oil and other fluids as desired for performing various well operations periodically.

In carrying out the method of this invention, it will be understood that the tubing P is initially inserted with the injector apparatus A (FIG. 1), and with a check valve 50 at the lower end of the tubing string P. The check valve 50 permits flow downwardly and outwardly, but prevents the return of flow upwardly so that well pressure within the well cannot flow upwardly through the tubing P.

When it becomes desirable to remove the wellhead equipment W, the injector apparatus A and the other apparatus above the tubing hanger T, the tubing gripping and supporting means, including the plurality of gripping members 20 are actuated to engage the pipe P. Such engagement is accomplished by rotating the operating or actuating rods 21 to move them inwardly towards each other to thereby force the gripping members 20 inwardly so that the gripping teeth 20a bite into the external surface of the tubing P. Thus, even though the external surface of the tubing P is smooth and without any collars or joints, the tubing P is securely gripped by the teeth 20a (FIG. 4).

The packing means, including the packing member 30 is next actuated so as to provide a fluid seal externally of the tubing P. This is accomplished by rotating the actuator 12, using a spanner wrench fitting into the spanner openings 12d, or any other suitable means, to cause the actuator 12 to unthread from the threads a and to make up the threads on the threads 11a so as to move from the position shown in FIG. 2 to the position shown in FIG. 4. During the rotational movements of the actuator 12, it also moves longitudinally downwardly and due to the engagement of the shoulder 120 with the shoulder 32c, the sleeve 32 is moved downwardly to longitudinally impress and thereby laterally distort the packing member 30 into sealing engagement with the external surface of the tubing P (FIG. 4).

With the tubing P thus supported and sealed off externally, the wellhead equipment W may be removed, together with all of the other equipment above the tubing hanger assembly T. The pipe or tubing P is then cut off at a point in proximity to the upper end of the tubing hanger T (FIG. 4), and the control or closure assembly K is mounted as shown in FIG. 4. The structure may then be left unattended for extended periods of time, but it is available for use when desired at periodic intervals.

The forgoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

We claim: 1. A method of mounting a tubing in a well pipe and a tubing hanger therebelow, wherein the tubing hanger has a tubing gripping and supporting means and a packing means, and with a wellhead assembly thereabove, and wherein the tubing string has a check valve at its lower end and the well is under pressure,

comprising the steps of:

initially positioning the tubing in the bore of the wellhead assembly and the tubing hanger, with the check valve on the tubing located in well pipe below the tubing hanger;

conducting well operations through the tubing while supporting the tubing above the wellhead assembly and prior to engagement by said tubing gripping and supporting means and said packing means;

thereafter engaging the tubing gripping and supporting means with the tubing to grip same and to thereby support same;

subsequently forcing the packing means into sealing engagement with the external surface of the tubing to prevent fluid flow around the tubing;

removing the wellhead assembly from the tubing hanger to expose the tubing above the tubing hanger; and

then cutting off the tubing above the hanger.

2. The method set forth in claim 1, including: installing a control assembly at the upper end of the tubing hanger to enclose the upper end of said tubing after it has been cut. 

1. A method of mounting a tubing in a well pipe and a tubing hanger therebelow, wherein the tubing hanger has a tubing gripping and supporting means and a packing means, and with a wellhead assembly thereabove, and wherein the tubing string has a check valve at its lower end and the well is under pressure, comprising the steps of: initially positioning the tubing in the bore of the wellhead assembly and the tubing hanger, with the check valve on the tubing located in well pipe below the tubing hanger; conducting well operations through the tubing while supporting the tubing above the wellhead assembly and prior to engagement by said tubing gripping and supporting means and said packing means; thereafter engaging the tubing gripping and supporting means with the tubing to grip same and to thereby support same; subsequently forcing the packing means into sealing engagement with the external surface of the tubing to prevent fluid flow around the tubing; removing the wellhead assembly from the tubing hanger to expose the tubing above the tubing hanger; and then cutting off the tubing above the hanger.
 2. The method set forth in claim 1, including: installing a control assembly at the upper end of the tubing hanger to enclose the upper end of said tubing after it has been cut. 